Biological Activity

Protocol

Technical Information

Purity & Documentation

References

Abiraterone (Abi) acetate is an ester prodrug of the anticancer agent Abiraterone, which shows IC50 values of 15 nM and 2.5 nM for the 17,20-lyase and 17α-hydroxylase (CYP17 is a bifunctional enzyme with both 17α-hydroxylase and 17,20-lyase activity). Abiraterone inhibits human 17,20-lyase and 17α-hydroxylase with IC50 of 27 and 30 nM respectively[1].
Significant inhibition of proliferation of the AR-positive prostate cancer cell lines LNCaP and VCaP with doses of Abiraterone ≥5 μM is confirmed[2]. Abiraterone inhibits recombinant human 3βHSD1 and 3βHSD2 activity with competitive Ki values of 2.1 and 8.8 μM. 10 μM Abiraterone is sufficient to completely block synthesis of 5α-dione and DHT in both cell lines.Treatment with Abiraterone significantly inhibited CRPC progression in the robustly growing subset, effectively putting a ceiling on tumor growth over 4 weeks of treatment (P<0.00001)[3].

In Vivo

Abiraterone (Abi) acetate prolongs survival in castration-resistant prostate cancer (CRPC). [3H]-dehydroepiandrosterone (DHEA) depletion and Δ4-androstenedione (AD) accumulation are inhibited by Abiraterone in LNCaP, with an IC50<1 μM. The 0.5 mmol/kg/d Abiraterone treatment dose is previously shown to yield serum concentrations of about 0.5 to 1 μM. Xenograft tumor growth in the control group is widely variable, with some tumors growing slowly and only a subset of tumors exhibiting robust growth[3].

Abiraterone acetate is dissolved in DMSO and then diluted to a maximum DMSO concentration of 0.2%[2].

LNCaP and VCaP cells are seeded in 96-well plates and grown in CSS-supplemented phenol red-free or FBS-supplemented media for 7 days. Cells are treated with Abiraterone (5 μM and 10 μM) at 24 and 96 hours after plating and cell viability is determined on day 7 by adding CellTiter Glo and measuring luminescence[2]. MCE has not independently confirmed the accuracy of these methods. They are for reference only.

Mice[3]Male NOD/SCID mice 6 to 8 weeks of age are surgically orchiectomized and implanted with a 5 mg 90-day sustained release DHEA pellet to mimic CRPC with human adrenal physiology. Two days later, 7×106 LAPC4 cells are injected subcutaneously with Matrigel. Tumor dimensions are measured 2 to 3 times per week, and volume is calculated as length×width×height×0.52. Once tumors reach 300 mm3, mice are randomly assigned to vehicle or Abiraterone treatment groups. Mice in the Abiraterone group are treated with 5 mL/kg intraperitoneal injections of 0.5 mmol/kg/d (0.1 mL 5% benzyl alcohol and 95% safflower oil solution) and control mice with vehicle only, once daily for 5 days per week over a duration of 4 weeks (n=8 mice per treatment). Statistical significance between Abiraterone and vehicle treatment groups is assessed by ANOVA based on a mixed-effect model. MCE has not independently confirmed the accuracy of these methods. They are for reference only.